Copolymerization of alpha olefins with sterically hindered alkenyl amines using ziegler catalysts

ABSTRACT

Alpha-olefins are copolymerized with a sterically hindered alkenyl amine in the presence of an organo-metal-transition metal catalyst (Ziegler-type catalyst). Copolymers are produced having 0.07 to 0.5 weight percent nitrogen in the copolymer.

United States Patent [1 1 Langer, Jr. et a1.

[451 Aug. 28, 1973 COPOLYMERIZATION OF ALPHA OLEFINS WITH STERICALLYHINDERED ALKENYL AMINES USING ZIEGLER CATALYSTS [75] Inventors: ArthurW. Langer, Jr., Watchung,

N.J.; Raymond R. Haynes, Baytown, Tex.

[73] Assignee: Esso Research and Engineering Company, Linden, NJ.

[22] Filed: June 25, 1965 [21] Appl. No.: 467,109

[52] US. Cl 260/88.l PN, 8/39, 8/41, 8/42, 8/168, 260/88.1 PA

[51] Int. Cl. C08f 15/00, C08f 45/66 [58] Field of Search 260/88.l, 88.1PX, 260/88.3, 88.3 L

[56] References Cited UNITED STATES PATENTS 3,293,326 12/1966 Jezl et al260/878 Feldhoff et a]. 260/88.l Marktscheffel et al 260/88.l

[57] ABSTRACT Alpha-olefins are copolymerized with a sterically hinderedalkenyl amine in the presence of an organo-metal-transition metalcatalyst (Ziegler-type catalyst). Copolymers are produced having 0.07 to0.5 weight percent nitrogen in the copolymer.

5 Claims, No Drawings COPOLYMERIZATION F ALPHA OLEFINS WITH STERICALLYHINDERED ALKENYL AMINES USING ZIEGLER CATALYSTS The invention may bebriefly described as the copolymerization of an alpha-olefin with asterically hindered alkenyl amine in the presence of anorganometaltransition metal catalyst (a Ziegler-type catalyst) toproduce new and useful copolymers.

Polymers produced by the polymerization of alphaolefins with anorgano-metal-transition metal catalyst (a Ziegler-type catalyst) haveheretofore been prepared which are useful in a number of applications.Heretofore, the polymerization of alpha-olefins with a Ziegler-typecatalyst to form polymers of high molecular weights and characteristicswhich have commercial importance have been formed expressly in theabsence of polar compounds due to the adverse effect such polarcompounds have on the catalyst.

It is an object of the present invention to polymerize alpha-olefinswith an alkenyl amine wherein the polar amine site is stericallyhindered.

Another object of the present invention is to copolymerize alpha-olefinsand sterically hindered alkenyl amines employing a Ziegler-typecatalyst. The sterically hindered alkenyl amines employed havesufficient steric hindrance at the amine site so that the nitrogen ofthe amine and the Ziegler-type catalyst do not interact to deactivatethe catalyst.

Still another object is to produce a copolymer having sufficientsterically hindered alkenyl amine incorporated in the structure so thatthe copolymer may be easily dyed with available dyes or otherwisemodified.

A specific object is to copolymerize propylene and an alkenyl hinderedamine so as to form a copolymer having many of the physical propertiesof polypropylene but which may be dyed, painted, or modified due to thepresence of the alkenyl hindered amine in the structure.

Other objects in accordance with this invention will be apparent fromthe more detailed disclosure set forth hereinafter.

The use of a Ziegler-type catalyst in the polymerization ofalpha-olef'ms to form homopolymers and certain copolymers such asethylene propylene and ethylene-butene is well known. Anorgano-metal-transition metal catalyst (a Zieglertype catalyst) isdefined for the purpose of this application as a transition metalcompound of Group IV, V, VI or VII of the Periodic Table which is atleast partially reduced and an organometallic compound of a metalselected from an alkali metal, an alkaline earth metal, zinc oraluminum. The transition metal compound may be reduced by means ofchemical reaction such as using the organo-metallic compound as areducing agent (e.g. Ziegler Belgian Pat. No. 533,362) or by usingradiation, etc. Exemplary of the transition metal compounds are thehalides such as the halides of titanium, zirconium, hafnium, thorium,uranium, vanadium, columbium, tantalum, chromium, molybdenum, tungsten,and mixtures thereof. The Ziegler-type catalyst may be prepared byreducing a transition metal compound such as titanium tetrachloride,titanium tetrabromide, zirconium tetrachloride, and the like by admixingwith a reducing agent such as an aluminum alkyl or other reducingorganometallic compounds or by starting with a prereduced transitionmetal compound such as titanium trichloride or titanium dichloride.

The organo-metallic compound acts as the activator component of thecatalyst. As mentioned above, the organo-metallic compound is sometimesused both as a reducing agent and as the activator component of thecatalyst. Exemplary of the organo metallic compounds are the alkyl oraryl derivatives of Group I-III metals, such as butyllithium,phenylsodium, diethyl magnesium, diethyl zinc, and the like. Preferredare the aluminum alkyls such as triethylaluminum, triisobutylaluminum,diethylaluminum chloride, ethylaluminum dichloride, diisobutylaluminumbromide, ethylalaminum propoxide, diethylaluminum hydride, and the like.

A preferred catalyst of the above type and one of the most active wasfound to be crystalline titanium chloride cocrystallized with aluminumchloride. The cocrystallized material is used together with an aluminumalkyl, e.g. triethylaluminum. The preferred catalyst has been preparedby a number of methods; see, for example, US. Pat. Nos. 3,032,509;3,032,511; 3,032,513; and 3,128,252 to A. W. Langer, .lr., and E.Tomquist. Another catalyst which is suitable is titanium trichloride andtriethylaluminum.

It is understood that the organo-metaltransition metal catalysts used inthe polymerization of the present invention may be modified by a thirdcomponent. The third component is used primarily to improve thestereoregularity of the polymer produced. Such third component materialsmay be certain Lewis bases, am monium salts, or coordinate-covalentcompounds such as hexamethylphosphoramide, tetrabutylammonium chlorideand the like.

The copolymerization according to the present invention may be carriedout in a wide variety of ways. The copolymerization process may be abatch or continuous operation and may be carried out with or without theuse of an inert organic diluent as the reaction medium. It is preferredto carry out the copolymerization in an inert liquid organic diluent asthe reaction medium. The inert liquid organic diluent may be analiphatic hydrocarbon such as hexane, heptane; a cycloaliphatichydrocarbon such as cyclohexane; an aromatic hydrocarbon such as xylene;halogenated aromatics such as chlorobenzene; or other known inertorganic diluents or mixtures of such hydrocarbons.

The selection of the temperature and pressure used for thecopolymerization process will depend upon the activity of the catalystbeing used and the diluent used. In general, the copolymerization mayvary over a wide range of temperatures and pressures. Using thepreferred catalysts which may be represented as TiCl l/3AlCl AlEt, andTiCl -,+AlEt,, the temperature may range from about 30 to 150 C.,preferably from 50 to 100 C. at a pressure of l to 10 atmospheres. Aparticularly suitable condition for the copolymerization is C. at oneatmosphere.

According to the prior art, polar compounds, such as alcohol, water,acetone, etc., have been used in polymerization processes usingZiegler-type catalysts to quench the polymerization mixture when thedesired degree of polymerization has been reached. The polar compoundshave been used in that they destroy the catalyst. According to thepresent invention a sterically hindered alkenyl amine which is analkenyl amine wherein the amine polar site is sterically hindered, iscopolymerized with an alpha-olefin in the presence of a Ziegler-typecatalyst without destroying the catalyst. It has been found according tothe present invention that a Ziegler-type catalyst will not be destroyedif the amine site is sufficiently sterically hindered.

The sterically hindered alkenyl'amines which may be used in thecopolymerization process of the present in vention has one of thefollowing formulae:

where: R is an alkenyl radical containing 4 to 12 carbons atoms;

R and R are hydrogen or an alkyl group containing 1 to 8 carbon atoms,but with the sum of carbon atoms in R and R being less than 13;

R is an alkyl group containing 1 to 4 carbon atoms;

R is hydrogen or an alkyl group containing 1 to 4 carbon atoms;

R is an alkenyl radical containing 2 to 12 carbon atoms; provided of thegroups R,, R and R at least two of the groups have a carbon branch atthe alpha and/or beta positions from the nitrogen atom; of the group Rit may be hydrogen if the group R has a carbon branch at the alpha orbeta position from the nitrogen atom.

Examples of suitable hindered amines which may be used as monomersaccording to the present invention are N,N-diisobutyl-3-butenylamine;N,N-diisopropyl-7- octenylamine; N,N-disec-butyl-4-pentenylamine; N,N-diisopropyl- 1 -methyl-6-heptenylamine; N-t-butyl- 1methyl-6-heptenylamine; N-(Z-ethylhexyl)-2-ethyl-4- pentenylamine;N-(4'-pentenyl)-2,6- dimethylpiperidine;2,6-di-t-butyl-4-vinylpiperidine; N-( S-hexenyl )2 ,5-dimethylpyrrolidine; N 7 -octenyl 2,5-dimethyl phrrole;N-(7-octenyl)2,5-dimethylpyrroline; N-( l-methyl-6-heptenyl)-2-methylpyrrolidine; 2,6-diisopropyl-4-vinylpyridine and the like.

As is set forth in the foregoing specific example as well as in theabove formulae, a hindered amine is defined as an amine or nitrogencompound wherein there are at least two carbon branches at the alpha orbeta positions from the nitrogen atom.

The alpha-olefin monomers used in the copolymerization process of thepresent invention are selected from the alpha-olefins having 2 to 10carbon atoms. The preferred alpha-olefin is propylene. Other suitablealpha-olefins which may be used are ethylene; 1- butene;3-methyl-l-butene; l-pentene; 4-methyl-1- pentene; l-hexene;4-methyl-l-hexene; S-methyl-lhexene; and the like. A mixture of two ormore of the above monomers may be used according to the presentinvention also. That is, a terpolymer of, for example, ethylene,propylene, and the sterically hindered alkenyl amine may be prepared bya batch or continuous process employing single or multiple seriesreactors.

The copolymerization of the present invention is preferably carried outby dispersing the Ziegler-type catalyst in an inert organic solvent andthen adding thereto the desired amount of sterically hindered alkenylamine. To the mixture of catalyst and sterically hindered alkenyl amineis added an alphaolefin or mixtures of alpha-olefins. By this procedurethe relative amount of sterically hindered alkenyl amine which iscopolymerized is controlled by the relative concentration of thesterically hindered alkenyl amine to alphaolefin. The molar ratio ofsterically hindered alkenyl amine to alpha-olefin is maintained between1:10 and 10:1 to obtain copolymers having 0.2 to 10 weight percenthindered amine in the backbone. Preferably, the molar ratio ofsterically hindered alkenyl amine to alpha-olefin is 1:6 to 3:1. Apreferred copolymer for dyeing will have from 1 to 5 weight percenthindered amine in the copolymer. Expressed in terms of nitrogen, apreferred copolymer would contain 0.07 to 0.5 weight percent nitrogen.

A copolymer as used in this application is defined as on page 36 ofFlory's, Principles of Polymer Chemistry, Cornell University Press(1953) which states:

Polymeric substances containing two or more structural units combinedmore or less in random sequence are then distinguished by the termcopolymer.

The copolymers of the present invention are characterized by thesterically hindered alkenyl amine monomers and the alpha-olefinmonomers.

The dyeable copolymers of this invention may be blended withalpha-olefin homopolymers or copolymers to obtain a variety of newcompositions. For example, homopolymers of ethylene or propylene orcopolymers of ethylene and propylene may be blended with the copolymerof this invention so long as the amount blended does not unduly minimizethe superior properties for the use intended.

The invention will be further illustrated by the following specificexamples which are given by way of illustration and not as limitationson the scope of the invention.

EXAMPLE 1 To a l-liter reactor was added 500 ml. xylene, 1.3 mmoles ofTiCl -1/3 AlCl 3.6 mmoles of triethyl alu minum, 1.8 mmoles ofhexamethylphosphoramide, and 56 mmoles of N,Ndiisopropyl-7-octenylamine. Propylene was added at the rate of 3moles/hr. and the reaction mixture was brought to C. and maintained atthat temperature for 1 hour. The reaction was then killed by pouring themixture into 500 ml. methanol. The precipitated polymer was removed byfiltration and washed twice in a Waring Blender with 200 ml. portions ofmethanol. The product was vacuum dried, and it weighed 42.6 g.Extraction of the polymer gave the following data:

Ether solubles Heptane solubles Heptane insolubles 9 The nitrogencontent of the total polymer was 0.16 percent. The ether and heptanesoluble fractions both contained 0.36 percent nitrogen. The heptaneinsoluble fraction contained 0.13 percent nitrogen.

An identical polymerization, but in the absence of N-,N-diisopropyl-7-octenylamine yielded 43.2 g. of polymer. Uponextraction, 1.0 weight percent was ether soluble, 5.6 weight percent washeptane soluble, and 93.4 weight percent was heptane insoluble.

EXAMPLE 2 Butene-l and N,N-diisopropyl-7-octenylamine.were polymerizedas described in Example 1 except no hexamethylphosphoramide was added.The polymer- 5 ization gave 33.0 g. of a polymer with 0.32 percent Nwhen 45 mmoles of the amine was added to the polymerization.

An identical polymerization, except in the absence of the amine, yielded34.0 g. of polybutene-l.

From the foregoing examples, it is evident that copolymers may be formedwith the sterically hindered alkenyl amine monomers and a variety ofalpha-olefins with no loss in catalyst activity.

EXAMPLES 3-7 Polymerizations were carried out using the proceduredescribed in Example 1 and a catalyst consisting of 1.3 mmoles Ti C1-,-l/3 AlCl and 3.6 mmoles AlEt but varying the alkenyl amineconcentrations for a hindered and non-hindered amine. The results areshown in Table 1.

TABLE I Copolymerization of Propylene and Alkenylamines 1.3 mmoles Ticlrs AlCl 3.6 mmoles AlEt Relative Catalyst Nitrogen in Polar MonomerActivity Copolymer l.0 Hindered N,N-Diisopropyl- 0.98 0. l67-octenylamine (56 mmoles) N,N-Diisopropyl- 1.01 0.46 7-octenylamine(224 mmoles) Unhindered N,N-Diet.hyl-4- 0.99 0.01 pentenylamine (3.0mmoles) N,N-Diethyl-4- 0.06 0.04 pentenylamine (6.0 mmoles) All runswere at atmospheric pressure for a durationof 1 hour. The propylene feedrate was 3 moles/hr.

As can be seen from the foregoing examples, when the molar concentrationof the unhindered amine is greater than the molar concentration of AlEtthe catalyst system is deactivated (rel. activity=0.06). But,

when the molar concentration of the hindered amine is greater than themolar concentration of AlEt no decline in catalyst activity is observed.Since the percent nitrogen in the copolymer is determined by theconcentration of the alkenyl amine, the sterically hindered alkenylamines of the present invention allow levels of nitrogen unobtainablewith the unhindered amine.

EXAMPLES 81 0 N,N-diisopropyl-3FbutenyIamine, N,N-diisopropyl-4-pentenylamine, and N ,N-diisopropyl-S-hexeny1a1'nine were alsocopolymerized with propylene. The data for Y these polymerizations isgiven in Table 11. Conditions for these runs are identical to thosegiven in Example 1. No decrease in catalyst efficiency was noted inthese polymerizations.

4-pentenylamine (7O mmoles) N,N-diisopropyl- 0,19 S-hexenylamine (64mmoles) EXAMPLE 11- To a l-gallon reactor was added 1300 ml. of hexane,

158 mmoles of aluminum triethyl 79.6 mmoles titanium trichloride, and557 mmoles of N,N-diisopropy1- 7-octenyl amine. One hundred grams ofpropylene was added, causing the pressure to rise to 40 psig. Thetemperature increased to 166 F. and was maintained at 166i6 F. for thecourse of an hour during which time an additional grams of propylene wasadded. The reaction was then killed by the addition of 1300 ml. ofmethanol. The resulting slurry was stirred, filtered, and washed twicewith methanol in a Waring Blender to give 240 grams of polymer.Theresulting polymer was 80.1 wt. percent heptane insoluble andcontained 0.37 percent nitrogen. The polymerization under identicalconditions, except in the absence of the amine, yielded 242 grams ofpolymer insoluble. was 74 wt. percent heptane insoluble The copolymersof the present invention are especially suitable for dyeing. Withpresent technology a level of 0.08 percent nitrogen in the copolymer isnecessary for acceptable dyeability. Also, films and pads of thecopolymers, besides being dyeable, show receptiveness and fastness topainting and printing. The suitability of the copolymers of the presentinvention for dyeing is illustrated in the following example.

EXAMPLE 1 2 A copolymer of propylene and N,N-diisopropyl-7- octenylaminecontaining 0.18 percent nitrogen was melt spun and drawn 4:1 to give afiber whose dyeability was determined as follows:

A 3 percent dye bath was prepared on the basis of 30 parts by weight ofwater to 1 part of polymer. Each dye is employed in accordance with theinstructions provided by the manufacturer, and generally, are all usedin a hot aqueous dye bath. The dyes are employed in a concentrationbased on the weight of the fiber to be dyed in that bath. A detergent,Triton X100, at about 0.3 percent by weight was added to the dye bath,and the dye bath adjusted to a pH of 4.0 with acetic acid. The copolymerwas placed in the dye bath (205 F.) for one hour.

The copolymer of the present invention, when formed in fibers, pads orfilms and dyed under the foregoing conditions gave deep colors withlrgalan Yellow GL (C.l. Acid Yellow 114), Vialon Orange F (premetallizeddye of B.A.S.F.), Erio Anthracene Brilliant Blue 2 GL (C.l. Acid Blue40), Celanthrene Fast Blue (C.l. Disperse Blue 7), and similar dyes. Thedeep colors were retained even after scouring for 15 minutes at 1.60" F.in an aqueous solution containing 0.5 percent by weight of sodiumcarbonate and 0.5 percent of Triton X100.

A polypropylene fiber subjected to the abovedescribed dye bath becameonly very faintly stained, and when subjected to scouring retained nocolor.

For the purpose of the application the term alkenyl means the radicalhaving the following formula:

l-1,C=CH-(C,,H,, where n is 0 or a whole number.

The nature and object of the present invention having been completelydescribed and illustrated and the where: R is an alkenyl radicalcontaining 4 to 12 carbon atoms;

R and R are selected from the group consisting of hydrogen and an alkylgroup containing 1 to 8 carbon atoms, with the sum of carbon atoms of Rand R being less than l3;

R is an alkyl group containing 1 to 4 carbon atoms; R is selected fromthe group consisting of hydrogen and an alkyl group containing 1 to 4carbon atoms;

R, is an alkenyl radical containing 2 to 12 carbon atoms; and

of the groups R R, and R at least two of the groups have a carbon branchat the alpha or beta positions from the nitrogen atom; and R may behydrogen provided the group R, has a carbon branch at the alpha or betaposition from the nitrogen atom.

2. A copolymerization process according to claim l wherein saidalpha-olefin is propylene.

3. A process according to claim 2 wherein said organo-metal-transitionmetal catalyst is TiCl -l/3 AlCl +AlEt and the temperature is withintherange of 30 C. to 150 C. at a pressure of l to 10 atmospheres.

4. A process according to claim 3 wherein said amine and said propyleneare maintained in a molar ratio between ]:10 and 10:1.

5. A process according to claim 2 wherein said organo-metal-transitionmetal catalyst is selected from the group consisting of TiCl -l l3 AlCl-l-AlEt and TiCl +AlEt and the temperature is within the range of 50 C.to C. at a pressure of l to l0 atmospheres and the molar ratio of saidamine to propylene is 1:6 to 3:6.

2. A copolymerization process according to claim 1 wherein saidalpha-olefin is propylene.
 3. A process according to claim 2 whereinsaid organo-metal-transition metal catalyst is TiCl3.1/3 AlCl3+AlEt3 andthe temperature is within the range of 30* C. to 150* C. at a pressureof 1 to 10 atmospheres.
 4. A process according to claim 3 wherein saidamine and said propylene are maintained in a molar ratio between 1:10and 10:1.
 5. A process according to claim 2 wherein saidorgano-metal-transition metal catalyst is selected from the groupconsisting of TiCl3.1/3 AlCl3+AlEt3 and TiCl3+AlEt3 and the temperatureis within the range of 50* C. to 100* C. at a pressure of 1 to 10atmospheres and the molar ratio of said amine to propylene is 1:6 to3:6.